Master of Science / Department of Mechanical & Nuclear Engineering / Dale Schinstock / This thesis describes the design, development, and initial testing of the Mobile Reduced Gravity Simulator (MoRGS). MoRGS is a hoist with active force control, to be used in terrestrial environments with human test subjects for the simulation of partial gravity or zero gravity environments. It is to be used with the subject performing activities while being harnessed to the hoist. The following work here describes the mechanical design, structural and dynamic analyses, simulations used to aid in the control design and component selection, the development of unique control algorithms tailored to the objectives and uncommon dynamics of MoRGS, and initial testing performed without the use of human subjects. Major components of the MoRGS system include: AC servo motor, gearbox, custom-designed drum, pneumatic muscle, load cell, and a microprocessor. The system is designed to track the motion of the test subject over several meters of vertical travel at speeds of up to 2 Gs of acceleration. This allows for high performance during subject’s physical tests, including running on a treadmill and a climbing ladder. It is capable of offloading 50 lb. to 600 lb. and the level of desired reduced gravity is programmable. Results from testing of the system demonstrate that MoRGS system achieves its goals. It performs well, and the sensitivity of the force controller enables it to compensate for the most minute human motion disturbance.

<p>The objective of this thesis is to implement a basic, yet realistic, ESC system into the VTI simulator environment. This system is then validated to assure that it is working properly and provides a realistic behavior.</p><p>The implemented ESC system is used in a study, where the ESC system could be turned on and off, to evaluate the benefits of an ESC system after a side impact. This study shows that an ESC system may aid the driver in such a critical situation when the driver is unaware that a side impact will occur. With the ESC system active no driver lost control while with the system inactive there were five drivers that lost control, but deviations in initial speed give statistical difficulties, thus more tests are needed. In the case where the driver knows that an impact will occur the ESC system showed to stabilize the automobile faster and it is shown that an expected improvement in stabilization time is between 40 to 62 percent. It was also seen during this part of the scenario that 2 percent loss of control occurred with an active ESC system and 45 percent without.</p>

This paper involves the calculation for composition of different layer used in laser structure and the simulation of cavity, formed by creating air columns in the InGaAsP medium, for square lattice. The aim of this project is to fabricate approximately zero threshold current lasers. This project involves FDTD simulation for optimizing dimension of the device, fabrication of laser structure and finally characterization of the device structure. / Singapore-MIT Alliance (SMA)

Ombord på moderna fartyg finns möjligheten att navigera med enbart ECDIS. ECDIS är beroende av många olika delsystem för att kunna fungera optimalt. Failure Mode and Effect Anylysis (FMEA) är ett verktyg med vilket man kan undersöka ett specifikt system för att upptäcka eventuella konstruktionsfel och brister i produktionsdesignen. Detta examensarbete har med hjälp av en FMEA undersökt ECDIS simulatorerna vid Sjöfartshögskolan i Kalmar för att ta reda på hur ECDIS påverkas när ett eller flera av delsystemen kopplade till ECDIS fallerar. Syftet med denna undersökning har varit att upptäcka konstruktionsfel, brister och begränsningar i ECDIS systemet vid simulatorerna i Sjöfartshögskolan i Kalmar. Det kunde påvisas att ECDIS i vissa fall ej har avgett de larm som enligt tillverkaren skall varsko navigatören att ett delsystem har fallerat. Vidare har vissa funktioner i ECDIS ej fungerat enligt tillverkarens anvisningar samt att vissa simulatorfunktioner som skall kunna testa en specifik situation i en säker miljö ej har fungerat. / Modern ships have the ability to navigate with the use of ECDIS only. ECDIS is dependent on many subsystems to function optimally. Failure Mode and Effect Analysis (FMEA) is a tool with which you can examine a specific system to detect potential construction errors and deficiencies in the production design. This thesis has used a FMEA to investigate ECDIS simulators at Sjöfartshögskolan in Kalmar to examine how ECDIS was affected when one or more of the subsystems connected to ECDIS have failed. The purpose of this study was to detect design errors, deficiencies and limitations of the ECDIS simulators at Sjöfartshögskolan in Kalmar. It could be demonstrated that some of the alarms in ECDIS that should alert the navigator that a subsystem has failed not has worked according to the manufacturer´s instructions. Additionally has some features of ECDIS not operated according to the manufacturer's instructions and some simulator functions which should test a specific situation in a safe environment have not worked.

Simulering är en viktig del av utvecklingsarbetet för nya datorkort hos Centre of Excellence - Computers på Saab AB i Jönköping. Ju tidigare i utvecklingsarbetet som defekter och svagheter hos designen hittas desto enklare och mindre kostsamma blir ändringarna att införa. På CoE används simulerings och analysverktyget HyperLynx från Mentor Graphics för att simulera alla kritiska nät. På så sätt kan svagheter hos en design hittas redan innan prototypstadiet. För att simulatorn ska vara användbar krävs dock en kunskap om hur dess resultat korrelerar med verkligheten. Det leder till den övergripande frågeställningen för detta arbete, hur väl överensstämmer HyperLynx simuleringsresultat med verkligheten? Frågeställningen besvarades genom att jämföra simuleringsresultat med motsvarande uppmätta signaler på ett testkort. Resultaten visar att HyperLynx håller en mycket god kvalitet. För signalen i helhet överensstämmer kurvformerna väl både när det gäller vilka reflektioner som bildas och timingen för reflektionerna. Enda genomgående skillnaden mellan simuleringarna och mätningarna visar på något för små amplituder för de simulerade reflektionerna. / Simulations are an important part of the process of designing new computer boards at the Centre of Excellence - Computers at Saab AB in Jönköping. The earlier problems and weaknesses in the design can be found during the design process the less time and money it will take to fix them. The engineers at CoE uses HyperLynx, an analysis and simulation software from Mentor Graphics, to simulate all the critical nets at the board. By doing so, the majority of the problems can be fixed before the prototyping stage. However, the engineers need to know how the simulated signals relate to real signals if the simulator is to be useful. Therefore the question to be answered in this study is how well does the simulated signals in HyperLynx imitate real signals? The question was answered by comparing simulated signals with measurements of corresponding signals on a test board. Overall the shapes of the signals are matching for both which reflections occurs and the timing of the reflections. The only noticeable difference found throughout the study is a slightly smaller amplitude of the reflections for the simulated signals compared to the corresponding measured signal. Due to these results, HyperLynx can be considered a high quality simulator.

The objective of this thesis is to implement a basic, yet realistic, ESC system into the VTI simulator environment. This system is then validated to assure that it is working properly and provides a realistic behavior. The implemented ESC system is used in a study, where the ESC system could be turned on and off, to evaluate the benefits of an ESC system after a side impact. This study shows that an ESC system may aid the driver in such a critical situation when the driver is unaware that a side impact will occur. With the ESC system active no driver lost control while with the system inactive there were five drivers that lost control, but deviations in initial speed give statistical difficulties, thus more tests are needed. In the case where the driver knows that an impact will occur the ESC system showed to stabilize the automobile faster and it is shown that an expected improvement in stabilization time is between 40 to 62 percent. It was also seen during this part of the scenario that 2 percent loss of control occurred with an active ESC system and 45 percent without.

Endoscopy is an involved clinical practice requiring considerable skill in performing the procedure. Virtual reality together with haptics offers immersive, flexible, and cost-effective platform for training in endoscopic procedures. In this thesis, we present mechanical design, control, characterization, and integration of a novel endoscopic haptic simulator with three degrees of freedom. Related ideas, computations, and experiments that support endoscopy and endoscopic simulator are also investigated in this thesis. The haptic device is designed to reflect forces in the three important directions, namely, longitudinal, rotational, and radial directions. The mechanical design of the haptic device overcomes some of the limitations of the existing systems. The device provides large sustained output force and possesses low friction, low inertia and zero backlash. Dynamics-based feed-forward control algorithm is developed to achieve high fidelity and transparency in force-feedback. Tracking performance, transparency, and nonlinearity are all quantified using experiments designed to validate the control structure and to characterize the developed haptic device. The device is shown to apply a maximum continuous force of 11 N in the longitudinal direction, maximum continuous torque of 196 mN.m in the rotational DoF, and a maximum force of 1.5 N (at each of the four radial pads) in the radial direction. Furthermore, we also present the design of a novel compliant mechanism for the radial DoF. The circumferentially actuated compliant (CAC) mechanism is a planar, reversible, and single degree-of-freedom compliant mechanism that emulates controlled and responsive circularly shaped opening. The mechanism is designed in view of the anatomy of the throat and the special manoeuvre required for intubation of the endoscope into the oesophagus by avoiding the trachea. As part of the auxiliary work for the endoscopic simulator, we developed a computational technique for simulating the shape of the entire endoscope during endoscopy. Strain measurements made at discrete locations along the length of endoscope are used in the method. Strain measurement, stain interpolation, and shape reconstruction based on strain information are discussed. Furthermore, a method to predict the location of point forces acting on the endoscope tube during endoscopy is proposed. A novel concept of haptic playback for endoscopy is also investigated in this work. Haptic playback aids the endoscopists to recall both visual as well as haptic information from an earlier endoscopic session. The endoscopic playback concept is evaluated using psychophysical experiments. Through these experiments, we quantified haptic perception through the endoscope, the effect of temporal separation on haptic memory, and the interaction between haptic and visual information in sensory processing.

Användandet av simulatorer i utbildningar ökar mer och mer. Simulatorer har använts inom pilotutbildningar och inom medicinsk utbildning länge och det finns mycket forskning som stödjer deras effektivitet. Nu har simulatorerna blivit mer tillgängliga i och med den tekniska utvecklingen och har börjat användas för förarutbildningar. Däremot saknas samma gedigna vetenskapliga stöd som finns för pilotutbildningar och medicinsk utbildning. Det finns visst underlag för utbildning i riskmedvetenhet men inte så många andra färdigheter. Syftet med studien var att undersöka hur effektiv en simulator är vid utbildning av förare i Eco-driving. Till studien rekryterades 20 elever från Yrkesakademin som utbildas för behörighet C, tung lastbil. Studien var av mellangruppsdesign där experimentgruppen tränade Eco-drivingfärdigheter och data över bränsleförbrukning och hastighet samlades in. Kontrollgruppen fick en teoretisk utbildning i Eco-driving i form av en inspelad video. Experimentgruppen hade en signifikant förbättring av bränsleförbrukning men inte kontrollgruppen. Detta stödjer effektiviteten av simulatorbaserad utbildning av Eco-driving. Resultaten är även uppmuntrande till träning av liknande färdigheter som bland annat är av betydelse för trafiksäkerhet. Dessutom finns det goda möjligheter att minska kostnaderna vid förarutbildningar samtidigt som eleverna lär sig bättre. / The use of of simulators in education is increasing. The aviation and medical education have a long history of implementing simulator training and education. With a strong body of scientific research that validates their use in education. As the technical development has increased, the availability of affordable simulators has increased their use in driver education. Unfortunately the research is not as strong as with the aviation or medical education. There are some support that simulator-based education can improve hazard perception but not so many other skills. Therefore I want to examine the effectiveness of a simulator in teaching Eco-driving skills to drivers. 20 students from Yrkesakademin were recruited as they were learning to drive trucks. The study is of between group design where the experimental group practiced Eco-driving skills in the simulator. Data were collected of the participants fuel consumption and speed. The control group were shown a video lecture on Eco-driving. The experimental group did significant improve while the control group did not. These results support the effectiveness of simulator-based education of Eco-driving skills. It also is encouraging for similar driving skills that can have a significant effect on traffic safety. While there is encouraging evidence for reducing the cost of driver education at the same time the students learning is enhanced.

The usage of a robotic simulator hasprovidedthe advantages of the efficientdevelopment and testing of robotics applications, saving time and resources and making easier publics demonstrations. This thesis project consists on the simulation of a wheel loader at an industrial environment inthe cycle of material handling. For the development of the Project have been used the Robot Operating System (ROS) and Gazebo frameworks which allows to reproduce the 3D map of the work site as well as the robotic wheel loaderand simulate it in a realistic way. The developed softwarealsoprovidesthemechanism to drive the wheel loader throughthereproduced terrain, to controlthe movement of the different articulated joints of the robot, to recompile information of the environmentthroughdifferent sensors (Laser, Odometry, GPS, IMU, etc) and to provide of a waypoint routes to the robot. Furthermore the simulator will be able to reproduce and integrate an asphalt plant modelto the scenario. Allowing an interaction with the wheel loader, this will transport gravel from the piles of the terrain to the pocket of the asphalt plant.

Objective The present study aims to investigate whether drivers’ age and their experience with driving simulators could explain differences between a subjective estimation of system adaptation and a respective objective systematic measurement. Background Assessing valid measurements in driving simulators causes concern because driving simulators are not yet as realistic as real on-road driving scenarios. Common methods like pre-defined training sessions and self-appraisals of simulator adaptation might therefore be insufficient to ensure actual valid data. Hence, influential variables on this discrepancy are investigated. Method In total, N = 203 drivers participated in a training session and a subsequent testing session in a close-to-production driving simulator. Subjective adaptation was estimated by the drivers and an objective adaptation value was gathered on the basis of driving accuracy. The discrepancy between these two measures was calculated and related to age, self-reported driving experience and occurrence of previous adaptation. Results Subjective adaptation was significantly faster than objective adaptation but neither drivers’ age, experience, nor previous adaptation could explain this discrepancy. Discussion Results indicate that younger and older drivers likewise underestimate the time needed for adaptation. Measuring a subjective point of adaptation seems to be an insufficient measure to ensure simulator validity when assessing both older and younger drivers.